Wireless communications systems typically provide interconnect and/or dispatch voice communication services. Interconnect voice communication services are full-duplex and are typically provided by most wireless carriers as circuit-switched communications. Dispatch communication services are half-duplex and are commonly known as walkie-talkie or push-to-talk (PTT) types of calls, such as the service provided by Sprint Nextel Corporation under the trade name Direct Connect.
Wireless communication stations (such as cellular telephones, personal digital assistants (PDAs), laptop computers and/or the like) operate using a combination of hardware and software. As illustrated in FIG. 1a, a communications architecture for a wireless communication station includes a radio interface layer (RIL) 110 interposed between an operating system 105 and wireless modem 115. Radio interface layer 110 interfaces operating system 105 (and any associated applications or programs) with wireless modem 115, which allows the development of telephony services for operating system 105 independent of the particular type of wireless modem being implemented. For more information on a radio interface layer the interested reader is referred to “Radio Interface Layer (RIL) White Paper” by Microsoft Corporation (June 2004), the entire disclosure of which is herein expressly incorporated by reference.
While there has been much development of radio interface layers for interconnect voice communication services, there has been very little development of a radio interface layer that also provides functionality for dispatch communication services.